Jimmy, Lisa and Annie Magoffin. Jimmy and Annie are at boarding school in Brisbane.

ABC News: Caitlyn Gribbin

Greyhound Australia will ban unaccompanied passengers under 15 from using its services from September 3, citing safety and scheduling concerns.

The company notified customers via email, citing recent incidents where services were delayed and passengers inconvenienced after parents failed to show at bus stops to pick up their children. The children were taken to police stations.

The Isolated Children's Parents' Association has fielded calls from parents who are upset at the changes and face lengthy drives or expensive flights to get their children to boarding schools across the nation.

Queensland state president Tammie Irons said the changes were disappointing and would inconvenience rural and remote families who relied on the services.

"It'll be really disappointing for those families, to have this service not be able to be utilised," she said.

"We've heard nothing until just the last couple of days — no warning — I'm not sure if they've ever had any consultation or anything like that."

Students entering Somerville House girls' boarding school in Brisbane. Many boarding students use the service to travel long distances to and from their homes.